Dart: Removes all but native calls and the handle watcher from the snapshot.

mojo/dart/test/uri_base_test.dart

Index: mojo/dart/test/uri_base_test.dart
diff --git a/mojo/dart/test/uri_base_test.dart b/mojo/dart/test/uri_base_test.dart
index eb20d43bbc707694c0db2c88adca634cd5837067..353d0f133b1f770c64750ae0a7081219d42e0a57 100644
--- a/mojo/dart/test/uri_base_test.dart
+++ b/mojo/dart/test/uri_base_test.dart
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:mojo.core';
+import 'package:mojo/public/dart/core.dart' as core;
 
 main() {
   print("${Uri.base}");